doubleshik

摘要： 题目不难但是一开始把 180 °后面 。。结果一直WAClockHandsThe medieval interest in mechanical contrivances is well illustrated by the development of the mechanical clock, the oldest of which is driven by weights and controlled by a verge, an oscillating arm engaging with a gear wheel. It dates back to 1386.Clocks d 阅读全文